Sebastian JV Project
The Sebastian Gold Project is a joint-venture with Castlemaine Goldfields Limited (CGL) who owns 75% interest in the joint venture by meeting expenditure requirements. Ownership of Exploration Licence 3105 has now been transferred to CGL and the Company owns a contractual 25% interest.
The project is located approximately 14 kilometres northwest of the city of Bendigo. The main producer at Sebastian was the Frederick the Great Company which produced a total of 186,000 oz gold at an average grade of 10.4 g/t from depths approaching 250 metres.
Geology
The geological setting and style of mineralisation at Sebastian is similar to that at Bendigo and is typified by a folded sedimentary package of shales and mudstones alternating with sandier units in quite discrete packages. Mineralisation is predominantly controlled by west-dipping faults breaching an anticlinal hinge zone and forming dilation zones within predominantly sandy units in the east limb of the fold.
Drilling by Western Mining Corporation Limited (WMC) in the 1980's into the Frederick the Great Anticline intersected a 20 metre (down hole) zone of quartz veining hosting pyrite and arsenopyrite and carbonate alteration in sandstone.
The best intersection was 0.6 metre with repeated assays varying from 18.3 – 31 g/t gold.
WMC never followed up this significant result or the potential for any down-plunge extensions of the main lode structure.
Exploration
The 2005 drilling programme by CGL followed up on earlier drilling by WMC. This phase of exploration confirmed the presence of a reef structure discovered by earlier WMC drilling as well as a parallel structure, now known as the ‘Bruhns Structure’.
This lies 90 metres east of the Frederick the Great Reef structure and has never been worked. The Bruhns is similar to the Frederick the Great because the structure also dips steeply to the west and cross cuts the eastern limb of the Frederick the Great Anticline.
The Sebastian JV has just completed its initial phase of drilling program, consisting of 5 diamond drill holes spaced on 200 metre sections and drilled to depths up to 425 metres.
This program confirmed that the Bruhns Structure has a strike length greater than 680 metres.
The 4 – 10 metre wide reef zone within the Bruhns Structure consists of massive quartz veins ranging from 0.5 to 1.5 metres in thickness with stylolitic laminations and adjacent spur veins in silicified sandstone and shale.
The quartz veins contain pyrite and arsenopyrite with minor chalcopyrite and rarer sphalerite and galena.
The gold assay data from Bruhns contain a small but significant population of higher grades. This behaviour is typical of the extremely high ‘Nugget Effect’ found in most Central Victorian gold deposits.
Such deposits are difficult to get representative samples. In Wattle Gully, for example, 98% of all drill assays were below 0.28 g/t gold from within a reef zone that produced half a million ounces at a recovered gold grade of 12 g/t gold. In the Frederick the Great Reef the average grade was 10.4 g/t gold.
The latest phase of drilling discovered a number of new west-dipping faults below the Bruhns Structure within the eastern limb of the Frederick the Great Anticline.
One fault was at the end of FTG006 containing 0.9 metres at 1.16 g/t gold from 350.1 metres. This discovery has significantly increased the probability of finding auriferous bearing fault structures repeating at depth, and the potential for a multiple reef system of substantial size.
Conclusion
Greater Bendigo is confident that aggressive ongoing exploration by its joint venture partner at Sebastian will lead to new and economic gold discoveries.
CGL to date has earned its 75% interest in the Joint Venture and Greater Bendigo has a 25% interest – requiring it to contribute 25% of the costs associated with the project or face dilution.